Flywheel spins without resistance?

J

jrol

Member
Ok, so I am not an engine guy, but I am learning slowly.

Mower: Murray Select 12.5HP/40"
Model: 405002X8a
Engine: Briggs and Stratton
Model: 28v707
Type: 1113-E1

Well it's kind of old, about 12-13 years maybe? Been running fine for the first month and a half or so of having it out and mowing after winter. Did all the usual things, charged batter, replaced gas (emptied before winter), and added oil and replaced blades. I go to mow last week and about 5 minutes into mowing it just locks up, sounded like when your blade hits something and stops your engine, but I didn't hit anything.

Longer story short, the flywheel was locked up and loosing up the bolt that holds the flywheel down and addig oil slowly loosened it up. So I tightened the bolt back, and now my problem is the flywheel turns way faster than usual and I don't see the carb doing anything or even a spark? I checked the magnet coils and spaced it properly, but not sure what the issue could be. It just spins like crazy and I have searched all over and can't find anyone that has had the same problem. If Any more info is needed, I will gladly oblige. Any help is appreciated, I am sure it is a lost cause, but you never know.
 
Sounds like maybe a flywheel key sheared. If the flywheel is 'locked up' that would indicate to me the engine as well was 'locked up' and adding oil helped lubricate it enough to free up. I don't see how loosening the flywheel nut would do anything but perhaps break loose the flywheel. Tightening it back down with enough torque shouldn't let the flywheel spin around at all really, even if the key is sheared. No spark could be from either a bad coil or sheared flywheel key, which would also make it kick back and hard to start. I'd venture a guess that when the engine suddenly seized up it sheared the flywheel key right then. Was the engine low on oil?
 
Looks to me like you need to lossen up the flywheel nut and pull the fly wheel and see it the key is good or bad, then if kep is good put it back together being sure key stays in place, one time i had a key slip out the bottom as I put the flywheel back on, tried to start & it back fired, i knew then what had happen, there are a couple tricks you can use to keep the key in place, 1 is a dab of heavy grease, the other is take a center punch and right on the edge of the key way put a light center punch mark on either side of the key way about mid way the key slot, this will make the key tight going in place,

If you motor locked up like You say i am wondering if something os wrong inside, pull the plug & make sure the piston is moving when you trun the fly wheel,

Rat
 
Re: 12 or 13???

redfish9 said:
buy a new mower
Click to expand...
I would definitely do that if it was in my current budget, however some unforseen events have eaten my savings, but I am still trying to sell my house so I have to keep it looking decent.

If I can do anything with this I will have to go to aarons, which is the LAST thing I want to do. I called autozone and o'reileys looking for a flywheel puller and they don't have them, so I guess I will check with lowes and home depot.
 
Re: 12 or 13???

Personally I don't use a fly wheel puller to get them of I just screw a bolt into the provided holes an pull it off with a claw hammer if you decide to do this then screw the fly wheel bolt in slightly in case it comes of fast you might find tapping it from side to side with a hammer and piece of wood. save money on a puller:smile:
 
20130602_155817.jpg

First off thanks for the replies, I appreciate it.

I think I can see what is the flywheel key. I have tried a couple of things to get it off with no luck. The bolts I have don't seem to be long enough to use a hammer with. I will keep googling, but does auto zone have one and they just don't know it?I thought I saw a picture of one on their site, but called and they said no it's just for vehicles. All lawnmower places around here are closed. =(
 
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